Catechism of the Catholic Church §2777 — excerpt
In the Roman liturgy, the Eucharistic assembly is invited to pray to our heavenly Father with filial boldness; the Eastern liturgies develop and use similar expressions: "dare in all confidence," "make us worthy of...."
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: St. Peter Chrysologus, Sermo 71, 3: PL 52, 401 CD